Grooved refiner plug and method for filling same



July 2, 1968 3,390,839

GROOVED REFINER PLUG AND METHOD FOR FILLING SAME H. R. SMITH Filed Nov. 12, 1965 MITH INVENTO HAROLD R. 3

ATTORNEYS United States Patent W 3,390,839 GROOVED REFINER PLUG AND METHOD FOR FILLING SAME Harold R. Smith, Georgetown, Mass., assignor to Bolton- Emerson, Inc., Lawrence, Mass., a corporation of Massachusetts Filed Nov. 12, 1965, Ser. No. 507,274 6 Claims. (Cl. 241-294) This invention relates to an improved plug, or bladed rotor, of the type having undercut, or dovetailed grooves, each groove seating a pair of spaced-apart bars, or knives.

In the Jordan engine, beater and allied arts, there have been many proposed solutions for anchoring the bars of the plug, or rotor, against displacement due to vibration, centrifugal force, or wear and tear. However, at present it is believed that the most widely used expedient is the undercutting of longitudinally extending slots in the plug body and seating a pair of spaced longitudinally extending bars in each undercut groove.

In US. Patent 2,862,424 to Jones of Dec. 2, 1958, the bars of each pair are separated by a filler, spacer or key of rectangular cross section, and of material which swells upon absorbing liquid, the expansion of the filler locking the bars in the groove. A similar filler of rectangular cross section is taught in US. Patent 3,004,725 to Prevost of Oct. 17, 1961, and a filler of inverted keystone cross section is disclosed in US. Patent 3,004,724, to Prevost of Oct. 17, 1961.

It will be apparent that a filler of inverted keystone cross section requires that the bars and fillers be assembled endwise of the plug, and that while fillers of rectangular cross section can be assembled either endwise or radially, there will be considerable friction, resistance to slidable engagement, and danger of fracturing the swellable filler by excessive pounding.

The disadvantage of rectangular or inverted tapered fillers is even more apparent, however, when it becomes necessary, due to wear of the bars, to remove the plug from the Jordan engine, remove the worn bars and install new bars. It is customary to first remove the wood separators from between the pairs of bars, by driving them out longitudinally from the small end of the plug to the large end. The fillers are then removed by driving a narrow bar, or pry, into the filler, between the bars, and prying upwardly, since endwise removal by driving is impractical. Since the recess between the inside faces of each pair of bars is either of identical width at top and bottom in the case of rectangular fillers, or is narrower at the top than at the bottom in the case of inverted keystone fillers, the upward prying procedure is hindered by excessive friction and by lack of space at the top of the dovetailed groove, which causes the bars and fillers to bind.

While those skilled in the art have heretofore avoided the use of fillers of keystone cross section in the belief that such fillers would pop out under the influence of expansion of the filler and/or of subsequent centrifugal force during high speed rotation, this invention makes use of fillers of this shape. I have found that the provision of inwardly convergent inside faces on the bars of each pair and the provision of a liquid swellable filler of keystone cross section between the bars, not only makes assembly and disassembly more rapid and eflicient, but also forms an assembly which is firmly anchored in the grooves in a manner equal to, or superior to, the devices of the prior art.

The tapered fillers of this invention have smooth flat side faces but the inside faces of the bars are preferably provided with looking recesses in the form of continuous grooves into which a narrow strip of the liquid swellable filler may expand. In assembly, two plug bars may be 3,390,839. Patented July 2, 1968 inserted partially, from a radial direction into the undercut groove, in tilted, or flared position. The tapered filler is then driven radially between the bars to snap the base portions of the bars into final position seated and anchored in the groove in semi-locked state. Final locking of all of the pairs of bars is accomplished by endwise installation of the wood separators between the pairs of bars and subsequent swelling of the fillers and separators in water or in paper stock.

The tapered fillers of the invention may be easily removed, radially, by simply breaking the lock of the narrow filler strip in the bar grooves, whereupon the filler moves upwardly radially and out of the filler recesses with minimum frictional, or other, resistance.

The principal object of the invention is therefore, to provide a double bladed, slotted Jordan engine plug which is no more costly than conventional plugs of the type but which is more easily assembled and disassembled.

Another object of the invention is to provide a method for assembling a double bladed, slotted plug, or rotor, in which the fillers between the blades may be inserted and removed, radially with ease and without danger of fracture when radially driven into place.

A further object of the invention is to provide a novel, rugged, low-cost Jordan plug in which each pair of bars in each undercut groove is anchored in the groove by a swellable filler of keystone, or inwardly convergent taper, cross section and in which each filler is anchored against outward movement by a portion expanded into a recess in at least one of the bars.

Other objects and advantages of the invention will be apparent from the claims, the description of the drawings, and from the drawing, in which FIGURE 1 is a perspective view of the plug of a Jordan refiner constructed in accordance with the invention;

FIGURE 2 is a fragmentary, enlarged end view in perspective, of a pair of bars, and a tapered filler of the invention;

FIGURE 3 is an end view of the bars and filler shown in FIGURE 2;

FIGURE 4 is a perspective view of one of the tapered, keystone shaped fillers; and

FIGURE 5 is a view similar to FIGURE 3 showing the wedging of the filler to snap the bars into semi-locked position in the groove.

As shown in the drawing 30 is a typical double bladed rotor of a paper refiner, for example the frustro-conical plug of a Jordan engine. The plug 30 includes the tapered plug body 31, having a large end 32 and a small end 33, the body being mounted on the plug shaft 34. The frustro-conical surface 35 of plug 30 includes a plurality of undercut grooves 36, which are angularly spaced therearound to extend longitudinally, or axially, of the plug body. The undercut grooves 36 are conventionally of dovetail cross section, with a flat bottom wall 37, undercut side walls 38 and 39, and a mouth, or opening 40 of predetermined width. Alternate grooves 36 are full length and half length as is customary in the art, and the plug 30 is sometimes called, perhaps incorrectly, a slotted plug. Suitable end rings 41 held in place by bolts 42 are usually provided at each opposite end of the plug body 31.

A plurality of pairs 45, of plug bars, or knives, 46 and 47 are provided, one pair in each groove 36, the bars being substantially identical in configuration but reversed in back to back relationship. The bars 46 and 47 are of predetermined dimensions so that the divergent base portions 48 and 49 fit within a groove with the bars spaced apart to form a recess for receiving a filler, key, or spacer. The outside face of each bar includes an inwardly convergent face portion 50, 51, 52, or 53, so

wall of the groove when the bar bottom face 58 is firmly seated on the groove bottom wall 37 to lock the bar against outward movement due to centrifugal force.

As thus far described the plug of this invention is similar to the plugs disclosed in the above mentioned patents.

However, in this invention, the bars 46 and 47, of each pair of bars 45, are provided with flat, planar inside faces 60 and 61, at least in the base and intermediate portions thereof, which are inwardly convergent rather than parallel as in U.S. 2,862,424, and U5. 3,004,725 or inwardly' divergent as in US. 3,004,724. As explained above, the tapered, wedge-shaped, outwardly divergent recess 62 of keystone cross section, so formed between the opposed faces 60 and 61, would heretofore have been expected to be impractical and to cause a swellable filler to pop out during assembly, swelling, or use. .I have found that a filler, spacer or key 63, of material capable of swelling when immersed in liquid, such as wood, and of keystone cross section, can be advantageously mounted in each recess 62 between the bars of each pair to not only serve as a lock, but to also permit a wider opening between the bars for easier removal of the bar and filler unit in each groove. As shown in FIGURE 4, each filler 63 is preferably of wood and includes a pair of inwardly convergent side faces 64 and 65, a relatively narrow inner, or bottom, face 66, and a relatively wide outer, or top, face 67. It should be noted that the side faces 64 and 65, are flat, smooth and devoid of recesses although they could be provided with a roughened, frictional surface, if desired, so long as the filler can be inserted slidably, from a radial direction, into position between a pair of bars mounted in a groove (FIGURE 5).

As shown in FIGURE 5, the dimensions of the bars 46 and 47 are such that they cannot be inserted in the groove in back to back position, from a radial direction but can be inserted successively, by outward tilting of one bar relative to the other. In assembly the bars, 46 and 47, are flared, or tilted outwardly, as shown, whereupon the filler is driven between the bars to thereby snap the base portions 48 and 49 into semi-locked position within the groove. While the endwise insertion of the separators 54 or 55 between the pairs of bars, and the subsequent swelling of the fillers and separators would create circumferential counter forces tending to permanently anchor the bars in the grooves and the fillers between the bars, I prefer to provide locking means 70 to retain the fillers in place.

Locking means 70 comprises recess means 71 in at least one of the inside faces or 61 of the bars of each pair. Preferably, the recess means 71 is in the form of a continuous groove such as 72 or 73, oppositely disposed in the intermediate portion of each bar 46 and 47, close to the top face 67 of the filler. Upon swelling of the filllers 63, a narrow strip, on each side face 64 or 65 thereof, designated 74 and 75, expands into one of the grooves 72 or 73 to prevent outward movement of the filled due to centrifugal force.

When the plug 30 has become worn and requires replacement of the bars, the plug is removed from the Jordan engine, and replacement of the bars is facilitated by the keystone shaped recess 62 and keystone shaped bar filler 63. Unlike prior art plugs in which the fillers must be pried and chipped out of rectangular, or inverted keystone recesses, the wide outer opening of the recesses 62 permits access of tools and the fracture of the strips 74 and 75 permits the fillers 63 to be easily removed. Once the filler is removed, the bars will tilt to permit the separators to be removed, or if the separators are removed endwise as a first operation, the friction on the fillers is correspondingly reduced.

I claim:

1. In a Jordan plug of the undercut, dovetail groove type, the combination of: Y

a plurality of pairs of plug bars, each pair seated in one of said undercut, dovetail grooves, the bars of each pair having spaced-apart, opposed, inside faces defining an inwardly convergent recesstherebetween of keystone cross section, having inwardly convergent outside face portions defining, with the adjacent pairs of bars, inwardly divergent recesses of inverted keystone cross section and having outwardly divergent outside face portions, within said grooves, for anchoring said bars;

a plurality of separators composed of material which swells as it absorbs liquid, each said separator being of inverted, keystone cross section and located in one of said inwardly divergent recesses between adjacent pairs of bars, and

a plurality of fillers, of material which swells as it absorbs liquid, each said filler being of keystone cross section and located in one of said inwardly convergent recesses between the bars ofone of said pairs,

the inside faces of said bars, each having recess means therein, located outside of said grooves, to receive expanded portions of said filler for anchoring said filler against outward movement.

2. A Jordan plug as specified in claim 1, wherein each said pair of bars, when said bars are back to back without a filler therebetween, is of predetermined overall width, at the base of the said outwardly divergent, outside face portions thereof, greater than the width of each said groove,

whereby said pair of bars may be inserted in, and removed from, said groove radially in the absence of one of said fillers therebetween only by tilting the outer portions thereof away from each other.

3. In a Jordan plug of the undercut grooved type the combination of:

a plurality of pairs of bars, each pair having divergent base portions adapted to anchor said bars in the undercut of a groove when said bars are spaced apart from each other;

opposed, flat planar inside faces on each bar of each said pair of bars defining an inwardly convergent recess therebetween of keystone cross section for receiving a filler of keystone cross section;

a plurality of said fillers of keystone cross section, each said filler being unitary and of predetermined height extending from the bottom of a groove outwardly beyond said groove and being slidably mounted in one of the said inwardly convergent recesses between one of said pairs of bars; and

locking means, on said filler and bars in the portion thereof outside of said groove connecting eachsaid filler to the said inside faces of said bars for preventing outward radial movement thereof due to centrifugal force.

4. A Jordan plug as specified in claim 3, wherein said locking means comprises a pair of oppositely disposed grooves in the said inside faces of the bars of each said pair, each groove extending continuously from one end to the other of said bars,

and wherein said fillers are of material adapted to swell upon absorption of liquid, to thereby become anchored in said grooves. i

5. An easily refillable grooved plug for Jordan refiners,

said plug comprising:

a plug body having undercut dovetail grooves,

a pair of plug bars mounted in each said groove, in

spaced apart relation, to define an outwardly divergent filler recess, said recess extending from the bottom of said groove to well outside said groove;

a filler of keystone cross section and of liquid swellable material mounted in each said filler recess to tightly seat each said pair of bars in the groove thereof, said filler extending from the bottom of said groove to well outside said groove;

and a locking decess in at least one inside face of each pair of bars, in the portion thereof located outside of said groove into which the material of said filler is expanded for anchoring said filler against radial outward movement.

6. The method of assembling a Jordan engine plug of the type having an undercut, grooved plug body, a pair of plug bars, each having a base portion seatable in one of said grooves and a swellable, unitary filler of Keystone cross section seatable between the bars of each pair of bars, said method comprising the steps of:

forming a plurality of said fillers with smooth, planar and then subjecting said filled plug to liquid until all of said Keystone shaped fillers have expanded to firmly anchor the said base portions of said bars in said grooves and to lock said fillers in the said recesses in the inside faces of said bars,

whereby endwise insertion and removal of said bars and fillers is avoided and said expansibly locked Keystone shaped fillers are relatively easily removed by radial, upward prying from thereunder for replacement of worn bars.

References Cited UNITED STATES PATENTS ide faces, forming said bars with inwardly 60n- 2 2 iii 2 vergent smooth, planar faces containing at lea t one 222253 23 5 2? g:

I d I recess in the ortion thereof outsi e i g 3,004,724 10/1961 Prsvost 241 294 and forming said bars with divergent bases of greater overall width, when back to back, than the width of the opening of a groove,

successively around said plug first inserting a pair of WILLIAM W. DYER, JR., Primary Examiner.

W. D. BRAY, Assistant Examiner. 

1. IN A JORDAN PLUG OF THE UNDERCUT, DOVETAIL GROOVE TYPE, THE COMBINATION OF: A PLURALITY OF PAIRS OF PLUG BARS, EACH PAIR SEATED IN ONE OF SAID UNDERCUT, DOVETAIL GROOVES, THE BARS OF EACH PAIR HAVING SPACED-APART, OPPOSED, INSIDE FACES DEFINING AN INWARDLY CONVERGENT RECESS THEREBETWEEN OF KEYSTONE CROSS SECTION, HAVING INWARDLY CONVERGENT OUTSIDE FACE PORTIONS DEFINING, WITH THE ADJACENT PAIRS OF BARS, INWARDLY DIVERGENT RECESSES OF INVERTED KEYSTONE CROSS SECTION AND HAVING OUTWARDLY DIVERGENT OUTSIDE FACE PORTIONS, WITHIN SAID GROOVES, FOR ANCHORING SAID BARS; A PLURALITY OF SEPARATORS COMPOSED OF MATERIAL WHICH SWELLS AS IT ABSORBS LIQUID, EACH SAID SEPARATOR BEING OF INVERTED, KEYSTONE CROSS SECTION AND LOCATED IN ONE OF SAID INWARDLY DIVERGENT RECESSES BETWEEN ADJACENT PAIRS OF BARS, AND A PLURALITY OF FILLERS, OF MATERIAL WHICH SWELLS AS IT ABSORBS LIQUID, EACH SAID FILLER BEING OF KEYSTONE CROSS SECTION AND LOCATED IN ONE OF SAID INWARDLY CONVERGENT RECESSES BETWEEN THE BARS OF ONE OF SAID PAIRS, THE INSIDE FACES OF SAID BARS, EACH HAVING RECESS MEANS THEREIN, LOCATED OUTSIDE OF SAID GROOVES, TO RECEIVE EXPANDED PORTIONS OF SAID FILLER FOR ANCHORING SAID FILLER AGAINST OUTWARD MOVEMENT. 